I know that I don't have much knowledge about the evilness of microsoft. But I hate it considering the NSA thing. Then why are you OSM guys, saying us to use the bing images? Please answer me with a nice and elaborate answer or else my spirit of contributing to OSM will drain out. I like OSM's theme, but NOT when it is mentioning the name of bing/m.soft here.

Bing is just one of various potential datasources in addition to GPS traces, photos and similar imagery as well as local knowledge. We don't rely on them in any way, Bing has just granted us the right to trace from their aerial imagery. There is other aerial imagery available from which we are allowed to trace, but Bing has the largest coverage and often a pretty good resolution. And there are no drawbacks for us, OSM will remain a free geographic database.

Looking at the current global surveillance disclosures there is nothing you should be worried about. If you download Bing aerial imagery then the only information Microsoft, the NSA or any other intelligence agency are able to extract is:

Your current IP address

Which imagery you are downloading (and when)

Of course this allows them to guess your current location and recent visited places. But the same information can be extracted when looking at your recent edits. So as far as I can see there is no disclosure of additional information about you. And as already explained, you don't have to use Bing if you don't want to.

The request headers also contain the user-agent string. The information in the request headers would probably be unique among 2,000 to 5,000 requests. The more information about your browser that is sent with the request, the more unique your browser fingerprint is:
https://panopticlick.eff.org/

There is no requirement to credit bing if you are simply using OSM data and nobody has claimed so. You should however note the source at least in the changeset source tag if you are tracing from bing, just as you should do for any other source.

Naturally use of Bing imagery in general is governed by their terms of service, and if you are displaying bing imagery you need to abide by those, which will require displaying the required attribution, logo etc.

In the first few years of the project, all details were entered purely from survey (using handheld GPS devices), without any background imagery. Many contributors still use this method. I would strongly recommend it as a way of making a better map, over and above any concerns you may have about tracing one reseller's satellite imagery.

Personally I view Microsoft as largely a busted flush in the "evilness" stakes, and am delighted that they have made this contribution which helps OSM become a credible alternative to... shall we say... certain other large organisations whose current influence on the world may be rather more baleful.